diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/fscache/object.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/fscache/object.c | 892 |
1 files changed, 0 insertions, 892 deletions
diff --git a/ANDROID_3.4.5/fs/fscache/object.c b/ANDROID_3.4.5/fs/fscache/object.c deleted file mode 100644 index b6b897c5..00000000 --- a/ANDROID_3.4.5/fs/fscache/object.c +++ /dev/null @@ -1,892 +0,0 @@ -/* FS-Cache object state machine handler - * - * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. - * Written by David Howells (dhowells@redhat.com) - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - * - * See Documentation/filesystems/caching/object.txt for a description of the - * object state machine and the in-kernel representations. - */ - -#define FSCACHE_DEBUG_LEVEL COOKIE -#include <linux/module.h> -#include "internal.h" - -const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = { - [FSCACHE_OBJECT_INIT] = "OBJECT_INIT", - [FSCACHE_OBJECT_LOOKING_UP] = "OBJECT_LOOKING_UP", - [FSCACHE_OBJECT_CREATING] = "OBJECT_CREATING", - [FSCACHE_OBJECT_AVAILABLE] = "OBJECT_AVAILABLE", - [FSCACHE_OBJECT_ACTIVE] = "OBJECT_ACTIVE", - [FSCACHE_OBJECT_UPDATING] = "OBJECT_UPDATING", - [FSCACHE_OBJECT_DYING] = "OBJECT_DYING", - [FSCACHE_OBJECT_LC_DYING] = "OBJECT_LC_DYING", - [FSCACHE_OBJECT_ABORT_INIT] = "OBJECT_ABORT_INIT", - [FSCACHE_OBJECT_RELEASING] = "OBJECT_RELEASING", - [FSCACHE_OBJECT_RECYCLING] = "OBJECT_RECYCLING", - [FSCACHE_OBJECT_WITHDRAWING] = "OBJECT_WITHDRAWING", - [FSCACHE_OBJECT_DEAD] = "OBJECT_DEAD", -}; -EXPORT_SYMBOL(fscache_object_states); - -const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = { - [FSCACHE_OBJECT_INIT] = "INIT", - [FSCACHE_OBJECT_LOOKING_UP] = "LOOK", - [FSCACHE_OBJECT_CREATING] = "CRTN", - [FSCACHE_OBJECT_AVAILABLE] = "AVBL", - [FSCACHE_OBJECT_ACTIVE] = "ACTV", - [FSCACHE_OBJECT_UPDATING] = "UPDT", - [FSCACHE_OBJECT_DYING] = "DYNG", - [FSCACHE_OBJECT_LC_DYING] = "LCDY", - [FSCACHE_OBJECT_ABORT_INIT] = "ABTI", - [FSCACHE_OBJECT_RELEASING] = "RELS", - [FSCACHE_OBJECT_RECYCLING] = "RCYC", - [FSCACHE_OBJECT_WITHDRAWING] = "WTHD", - [FSCACHE_OBJECT_DEAD] = "DEAD", -}; - -static int fscache_get_object(struct fscache_object *); -static void fscache_put_object(struct fscache_object *); -static void fscache_initialise_object(struct fscache_object *); -static void fscache_lookup_object(struct fscache_object *); -static void fscache_object_available(struct fscache_object *); -static void fscache_release_object(struct fscache_object *); -static void fscache_withdraw_object(struct fscache_object *); -static void fscache_enqueue_dependents(struct fscache_object *); -static void fscache_dequeue_object(struct fscache_object *); - -/* - * we need to notify the parent when an op completes that we had outstanding - * upon it - */ -static inline void fscache_done_parent_op(struct fscache_object *object) -{ - struct fscache_object *parent = object->parent; - - _enter("OBJ%x {OBJ%x,%x}", - object->debug_id, parent->debug_id, parent->n_ops); - - spin_lock_nested(&parent->lock, 1); - parent->n_ops--; - parent->n_obj_ops--; - if (parent->n_ops == 0) - fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); - spin_unlock(&parent->lock); -} - -/* - * process events that have been sent to an object's state machine - * - initiates parent lookup - * - does object lookup - * - does object creation - * - does object recycling and retirement - * - does object withdrawal - */ -static void fscache_object_state_machine(struct fscache_object *object) -{ - enum fscache_object_state new_state; - struct fscache_cookie *cookie; - - ASSERT(object != NULL); - - _enter("{OBJ%x,%s,%lx}", - object->debug_id, fscache_object_states[object->state], - object->events); - - switch (object->state) { - /* wait for the parent object to become ready */ - case FSCACHE_OBJECT_INIT: - object->event_mask = - ULONG_MAX & ~(1 << FSCACHE_OBJECT_EV_CLEARED); - fscache_initialise_object(object); - goto done; - - /* look up the object metadata on disk */ - case FSCACHE_OBJECT_LOOKING_UP: - fscache_lookup_object(object); - goto lookup_transit; - - /* create the object metadata on disk */ - case FSCACHE_OBJECT_CREATING: - fscache_lookup_object(object); - goto lookup_transit; - - /* handle an object becoming available; start pending - * operations and queue dependent operations for processing */ - case FSCACHE_OBJECT_AVAILABLE: - fscache_object_available(object); - goto active_transit; - - /* normal running state */ - case FSCACHE_OBJECT_ACTIVE: - goto active_transit; - - /* update the object metadata on disk */ - case FSCACHE_OBJECT_UPDATING: - clear_bit(FSCACHE_OBJECT_EV_UPDATE, &object->events); - fscache_stat(&fscache_n_updates_run); - fscache_stat(&fscache_n_cop_update_object); - object->cache->ops->update_object(object); - fscache_stat_d(&fscache_n_cop_update_object); - goto active_transit; - - /* handle an object dying during lookup or creation */ - case FSCACHE_OBJECT_LC_DYING: - object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE); - fscache_stat(&fscache_n_cop_lookup_complete); - object->cache->ops->lookup_complete(object); - fscache_stat_d(&fscache_n_cop_lookup_complete); - - spin_lock(&object->lock); - object->state = FSCACHE_OBJECT_DYING; - cookie = object->cookie; - if (cookie) { - if (test_and_clear_bit(FSCACHE_COOKIE_LOOKING_UP, - &cookie->flags)) - wake_up_bit(&cookie->flags, - FSCACHE_COOKIE_LOOKING_UP); - if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, - &cookie->flags)) - wake_up_bit(&cookie->flags, - FSCACHE_COOKIE_CREATING); - } - spin_unlock(&object->lock); - - fscache_done_parent_op(object); - - /* wait for completion of all active operations on this object - * and the death of all child objects of this object */ - case FSCACHE_OBJECT_DYING: - dying: - clear_bit(FSCACHE_OBJECT_EV_CLEARED, &object->events); - spin_lock(&object->lock); - _debug("dying OBJ%x {%d,%d}", - object->debug_id, object->n_ops, object->n_children); - if (object->n_ops == 0 && object->n_children == 0) { - object->event_mask &= - ~(1 << FSCACHE_OBJECT_EV_CLEARED); - object->event_mask |= - (1 << FSCACHE_OBJECT_EV_WITHDRAW) | - (1 << FSCACHE_OBJECT_EV_RETIRE) | - (1 << FSCACHE_OBJECT_EV_RELEASE) | - (1 << FSCACHE_OBJECT_EV_ERROR); - } else { - object->event_mask &= - ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) | - (1 << FSCACHE_OBJECT_EV_RETIRE) | - (1 << FSCACHE_OBJECT_EV_RELEASE) | - (1 << FSCACHE_OBJECT_EV_ERROR)); - object->event_mask |= - 1 << FSCACHE_OBJECT_EV_CLEARED; - } - spin_unlock(&object->lock); - fscache_enqueue_dependents(object); - fscache_start_operations(object); - goto terminal_transit; - - /* handle an abort during initialisation */ - case FSCACHE_OBJECT_ABORT_INIT: - _debug("handle abort init %lx", object->events); - object->event_mask &= ~(1 << FSCACHE_OBJECT_EV_UPDATE); - - spin_lock(&object->lock); - fscache_dequeue_object(object); - - object->state = FSCACHE_OBJECT_DYING; - if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, - &object->cookie->flags)) - wake_up_bit(&object->cookie->flags, - FSCACHE_COOKIE_CREATING); - spin_unlock(&object->lock); - goto dying; - - /* handle the netfs releasing an object and possibly marking it - * obsolete too */ - case FSCACHE_OBJECT_RELEASING: - case FSCACHE_OBJECT_RECYCLING: - object->event_mask &= - ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) | - (1 << FSCACHE_OBJECT_EV_RETIRE) | - (1 << FSCACHE_OBJECT_EV_RELEASE) | - (1 << FSCACHE_OBJECT_EV_ERROR)); - fscache_release_object(object); - spin_lock(&object->lock); - object->state = FSCACHE_OBJECT_DEAD; - spin_unlock(&object->lock); - fscache_stat(&fscache_n_object_dead); - goto terminal_transit; - - /* handle the parent cache of this object being withdrawn from - * active service */ - case FSCACHE_OBJECT_WITHDRAWING: - object->event_mask &= - ~((1 << FSCACHE_OBJECT_EV_WITHDRAW) | - (1 << FSCACHE_OBJECT_EV_RETIRE) | - (1 << FSCACHE_OBJECT_EV_RELEASE) | - (1 << FSCACHE_OBJECT_EV_ERROR)); - fscache_withdraw_object(object); - spin_lock(&object->lock); - object->state = FSCACHE_OBJECT_DEAD; - spin_unlock(&object->lock); - fscache_stat(&fscache_n_object_dead); - goto terminal_transit; - - /* complain about the object being woken up once it is - * deceased */ - case FSCACHE_OBJECT_DEAD: - printk(KERN_ERR "FS-Cache:" - " Unexpected event in dead state %lx\n", - object->events & object->event_mask); - BUG(); - - default: - printk(KERN_ERR "FS-Cache: Unknown object state %u\n", - object->state); - BUG(); - } - - /* determine the transition from a lookup state */ -lookup_transit: - switch (fls(object->events & object->event_mask) - 1) { - case FSCACHE_OBJECT_EV_WITHDRAW: - case FSCACHE_OBJECT_EV_RETIRE: - case FSCACHE_OBJECT_EV_RELEASE: - case FSCACHE_OBJECT_EV_ERROR: - new_state = FSCACHE_OBJECT_LC_DYING; - goto change_state; - case FSCACHE_OBJECT_EV_REQUEUE: - goto done; - case -1: - goto done; /* sleep until event */ - default: - goto unsupported_event; - } - - /* determine the transition from an active state */ -active_transit: - switch (fls(object->events & object->event_mask) - 1) { - case FSCACHE_OBJECT_EV_WITHDRAW: - case FSCACHE_OBJECT_EV_RETIRE: - case FSCACHE_OBJECT_EV_RELEASE: - case FSCACHE_OBJECT_EV_ERROR: - new_state = FSCACHE_OBJECT_DYING; - goto change_state; - case FSCACHE_OBJECT_EV_UPDATE: - new_state = FSCACHE_OBJECT_UPDATING; - goto change_state; - case -1: - new_state = FSCACHE_OBJECT_ACTIVE; - goto change_state; /* sleep until event */ - default: - goto unsupported_event; - } - - /* determine the transition from a terminal state */ -terminal_transit: - switch (fls(object->events & object->event_mask) - 1) { - case FSCACHE_OBJECT_EV_WITHDRAW: - new_state = FSCACHE_OBJECT_WITHDRAWING; - goto change_state; - case FSCACHE_OBJECT_EV_RETIRE: - new_state = FSCACHE_OBJECT_RECYCLING; - goto change_state; - case FSCACHE_OBJECT_EV_RELEASE: - new_state = FSCACHE_OBJECT_RELEASING; - goto change_state; - case FSCACHE_OBJECT_EV_ERROR: - new_state = FSCACHE_OBJECT_WITHDRAWING; - goto change_state; - case FSCACHE_OBJECT_EV_CLEARED: - new_state = FSCACHE_OBJECT_DYING; - goto change_state; - case -1: - goto done; /* sleep until event */ - default: - goto unsupported_event; - } - -change_state: - spin_lock(&object->lock); - object->state = new_state; - spin_unlock(&object->lock); - -done: - _leave(" [->%s]", fscache_object_states[object->state]); - return; - -unsupported_event: - printk(KERN_ERR "FS-Cache:" - " Unsupported event %lx [mask %lx] in state %s\n", - object->events, object->event_mask, - fscache_object_states[object->state]); - BUG(); -} - -/* - * execute an object - */ -void fscache_object_work_func(struct work_struct *work) -{ - struct fscache_object *object = - container_of(work, struct fscache_object, work); - unsigned long start; - - _enter("{OBJ%x}", object->debug_id); - - start = jiffies; - fscache_object_state_machine(object); - fscache_hist(fscache_objs_histogram, start); - if (object->events & object->event_mask) - fscache_enqueue_object(object); - clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); - fscache_put_object(object); -} -EXPORT_SYMBOL(fscache_object_work_func); - -/* - * initialise an object - * - check the specified object's parent to see if we can make use of it - * immediately to do a creation - * - we may need to start the process of creating a parent and we need to wait - * for the parent's lookup and creation to complete if it's not there yet - * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the - * leaf-most cookies of the object and all its children - */ -static void fscache_initialise_object(struct fscache_object *object) -{ - struct fscache_object *parent; - - _enter(""); - ASSERT(object->cookie != NULL); - ASSERT(object->cookie->parent != NULL); - - if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) | - (1 << FSCACHE_OBJECT_EV_RELEASE) | - (1 << FSCACHE_OBJECT_EV_RETIRE) | - (1 << FSCACHE_OBJECT_EV_WITHDRAW))) { - _debug("abort init %lx", object->events); - spin_lock(&object->lock); - object->state = FSCACHE_OBJECT_ABORT_INIT; - spin_unlock(&object->lock); - return; - } - - spin_lock(&object->cookie->lock); - spin_lock_nested(&object->cookie->parent->lock, 1); - - parent = object->parent; - if (!parent) { - _debug("no parent"); - set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); - } else { - spin_lock(&object->lock); - spin_lock_nested(&parent->lock, 1); - _debug("parent %s", fscache_object_states[parent->state]); - - if (parent->state >= FSCACHE_OBJECT_DYING) { - _debug("bad parent"); - set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); - } else if (parent->state < FSCACHE_OBJECT_AVAILABLE) { - _debug("wait"); - - /* we may get woken up in this state by child objects - * binding on to us, so we need to make sure we don't - * add ourself to the list multiple times */ - if (list_empty(&object->dep_link)) { - fscache_stat(&fscache_n_cop_grab_object); - object->cache->ops->grab_object(object); - fscache_stat_d(&fscache_n_cop_grab_object); - list_add(&object->dep_link, - &parent->dependents); - - /* fscache_acquire_non_index_cookie() uses this - * to wake the chain up */ - if (parent->state == FSCACHE_OBJECT_INIT) - fscache_enqueue_object(parent); - } - } else { - _debug("go"); - parent->n_ops++; - parent->n_obj_ops++; - object->lookup_jif = jiffies; - object->state = FSCACHE_OBJECT_LOOKING_UP; - set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); - } - - spin_unlock(&parent->lock); - spin_unlock(&object->lock); - } - - spin_unlock(&object->cookie->parent->lock); - spin_unlock(&object->cookie->lock); - _leave(""); -} - -/* - * look an object up in the cache from which it was allocated - * - we hold an "access lock" on the parent object, so the parent object cannot - * be withdrawn by either party till we've finished - * - an object's cookie is pinned until we clear FSCACHE_COOKIE_CREATING on the - * leaf-most cookies of the object and all its children - */ -static void fscache_lookup_object(struct fscache_object *object) -{ - struct fscache_cookie *cookie = object->cookie; - struct fscache_object *parent; - int ret; - - _enter(""); - - parent = object->parent; - ASSERT(parent != NULL); - ASSERTCMP(parent->n_ops, >, 0); - ASSERTCMP(parent->n_obj_ops, >, 0); - - /* make sure the parent is still available */ - ASSERTCMP(parent->state, >=, FSCACHE_OBJECT_AVAILABLE); - - if (parent->state >= FSCACHE_OBJECT_DYING || - test_bit(FSCACHE_IOERROR, &object->cache->flags)) { - _debug("unavailable"); - set_bit(FSCACHE_OBJECT_EV_WITHDRAW, &object->events); - _leave(""); - return; - } - - _debug("LOOKUP \"%s/%s\" in \"%s\"", - parent->cookie->def->name, cookie->def->name, - object->cache->tag->name); - - fscache_stat(&fscache_n_object_lookups); - fscache_stat(&fscache_n_cop_lookup_object); - ret = object->cache->ops->lookup_object(object); - fscache_stat_d(&fscache_n_cop_lookup_object); - - if (test_bit(FSCACHE_OBJECT_EV_ERROR, &object->events)) - set_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags); - - if (ret == -ETIMEDOUT) { - /* probably stuck behind another object, so move this one to - * the back of the queue */ - fscache_stat(&fscache_n_object_lookups_timed_out); - set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); - } - - _leave(""); -} - -/** - * fscache_object_lookup_negative - Note negative cookie lookup - * @object: Object pointing to cookie to mark - * - * Note negative lookup, permitting those waiting to read data from an already - * existing backing object to continue as there's no data for them to read. - */ -void fscache_object_lookup_negative(struct fscache_object *object) -{ - struct fscache_cookie *cookie = object->cookie; - - _enter("{OBJ%x,%s}", - object->debug_id, fscache_object_states[object->state]); - - spin_lock(&object->lock); - if (object->state == FSCACHE_OBJECT_LOOKING_UP) { - fscache_stat(&fscache_n_object_lookups_negative); - - /* transit here to allow write requests to begin stacking up - * and read requests to begin returning ENODATA */ - object->state = FSCACHE_OBJECT_CREATING; - spin_unlock(&object->lock); - - set_bit(FSCACHE_COOKIE_PENDING_FILL, &cookie->flags); - set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); - - _debug("wake up lookup %p", &cookie->flags); - smp_mb__before_clear_bit(); - clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); - smp_mb__after_clear_bit(); - wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); - set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); - } else { - ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING); - spin_unlock(&object->lock); - } - - _leave(""); -} -EXPORT_SYMBOL(fscache_object_lookup_negative); - -/** - * fscache_obtained_object - Note successful object lookup or creation - * @object: Object pointing to cookie to mark - * - * Note successful lookup and/or creation, permitting those waiting to write - * data to a backing object to continue. - * - * Note that after calling this, an object's cookie may be relinquished by the - * netfs, and so must be accessed with object lock held. - */ -void fscache_obtained_object(struct fscache_object *object) -{ - struct fscache_cookie *cookie = object->cookie; - - _enter("{OBJ%x,%s}", - object->debug_id, fscache_object_states[object->state]); - - /* if we were still looking up, then we must have a positive lookup - * result, in which case there may be data available */ - spin_lock(&object->lock); - if (object->state == FSCACHE_OBJECT_LOOKING_UP) { - fscache_stat(&fscache_n_object_lookups_positive); - - clear_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags); - - object->state = FSCACHE_OBJECT_AVAILABLE; - spin_unlock(&object->lock); - - smp_mb__before_clear_bit(); - clear_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); - smp_mb__after_clear_bit(); - wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); - set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); - } else { - ASSERTCMP(object->state, ==, FSCACHE_OBJECT_CREATING); - fscache_stat(&fscache_n_object_created); - - object->state = FSCACHE_OBJECT_AVAILABLE; - spin_unlock(&object->lock); - set_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events); - smp_wmb(); - } - - if (test_and_clear_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) - wake_up_bit(&cookie->flags, FSCACHE_COOKIE_CREATING); - - _leave(""); -} -EXPORT_SYMBOL(fscache_obtained_object); - -/* - * handle an object that has just become available - */ -static void fscache_object_available(struct fscache_object *object) -{ - _enter("{OBJ%x}", object->debug_id); - - spin_lock(&object->lock); - - if (object->cookie && - test_and_clear_bit(FSCACHE_COOKIE_CREATING, &object->cookie->flags)) - wake_up_bit(&object->cookie->flags, FSCACHE_COOKIE_CREATING); - - fscache_done_parent_op(object); - if (object->n_in_progress == 0) { - if (object->n_ops > 0) { - ASSERTCMP(object->n_ops, >=, object->n_obj_ops); - ASSERTIF(object->n_ops > object->n_obj_ops, - !list_empty(&object->pending_ops)); - fscache_start_operations(object); - } else { - ASSERT(list_empty(&object->pending_ops)); - } - } - spin_unlock(&object->lock); - - fscache_stat(&fscache_n_cop_lookup_complete); - object->cache->ops->lookup_complete(object); - fscache_stat_d(&fscache_n_cop_lookup_complete); - fscache_enqueue_dependents(object); - - fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif); - fscache_stat(&fscache_n_object_avail); - - _leave(""); -} - -/* - * drop an object's attachments - */ -static void fscache_drop_object(struct fscache_object *object) -{ - struct fscache_object *parent = object->parent; - struct fscache_cache *cache = object->cache; - - _enter("{OBJ%x,%d}", object->debug_id, object->n_children); - - ASSERTCMP(object->cookie, ==, NULL); - ASSERT(hlist_unhashed(&object->cookie_link)); - - spin_lock(&cache->object_list_lock); - list_del_init(&object->cache_link); - spin_unlock(&cache->object_list_lock); - - fscache_stat(&fscache_n_cop_drop_object); - cache->ops->drop_object(object); - fscache_stat_d(&fscache_n_cop_drop_object); - - if (parent) { - _debug("release parent OBJ%x {%d}", - parent->debug_id, parent->n_children); - - spin_lock(&parent->lock); - parent->n_children--; - if (parent->n_children == 0) - fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED); - spin_unlock(&parent->lock); - object->parent = NULL; - } - - /* this just shifts the object release to the work processor */ - fscache_put_object(object); - - _leave(""); -} - -/* - * release or recycle an object that the netfs has discarded - */ -static void fscache_release_object(struct fscache_object *object) -{ - _enter(""); - - fscache_drop_object(object); -} - -/* - * withdraw an object from active service - */ -static void fscache_withdraw_object(struct fscache_object *object) -{ - struct fscache_cookie *cookie; - bool detached; - - _enter(""); - - spin_lock(&object->lock); - cookie = object->cookie; - if (cookie) { - /* need to get the cookie lock before the object lock, starting - * from the object pointer */ - atomic_inc(&cookie->usage); - spin_unlock(&object->lock); - - detached = false; - spin_lock(&cookie->lock); - spin_lock(&object->lock); - - if (object->cookie == cookie) { - hlist_del_init(&object->cookie_link); - object->cookie = NULL; - detached = true; - } - spin_unlock(&cookie->lock); - fscache_cookie_put(cookie); - if (detached) - fscache_cookie_put(cookie); - } - - spin_unlock(&object->lock); - - fscache_drop_object(object); -} - -/* - * withdraw an object from active service at the behest of the cache - * - need break the links to a cached object cookie - * - called under two situations: - * (1) recycler decides to reclaim an in-use object - * (2) a cache is unmounted - * - have to take care as the cookie can be being relinquished by the netfs - * simultaneously - * - the object is pinned by the caller holding a refcount on it - */ -void fscache_withdrawing_object(struct fscache_cache *cache, - struct fscache_object *object) -{ - bool enqueue = false; - - _enter(",OBJ%x", object->debug_id); - - spin_lock(&object->lock); - if (object->state < FSCACHE_OBJECT_WITHDRAWING) { - object->state = FSCACHE_OBJECT_WITHDRAWING; - enqueue = true; - } - spin_unlock(&object->lock); - - if (enqueue) - fscache_enqueue_object(object); - - _leave(""); -} - -/* - * get a ref on an object - */ -static int fscache_get_object(struct fscache_object *object) -{ - int ret; - - fscache_stat(&fscache_n_cop_grab_object); - ret = object->cache->ops->grab_object(object) ? 0 : -EAGAIN; - fscache_stat_d(&fscache_n_cop_grab_object); - return ret; -} - -/* - * discard a ref on a work item - */ -static void fscache_put_object(struct fscache_object *object) -{ - fscache_stat(&fscache_n_cop_put_object); - object->cache->ops->put_object(object); - fscache_stat_d(&fscache_n_cop_put_object); -} - -/* - * enqueue an object for metadata-type processing - */ -void fscache_enqueue_object(struct fscache_object *object) -{ - _enter("{OBJ%x}", object->debug_id); - - if (fscache_get_object(object) >= 0) { - wait_queue_head_t *cong_wq = - &get_cpu_var(fscache_object_cong_wait); - - if (queue_work(fscache_object_wq, &object->work)) { - if (fscache_object_congested()) - wake_up(cong_wq); - } else - fscache_put_object(object); - - put_cpu_var(fscache_object_cong_wait); - } -} - -/** - * fscache_object_sleep_till_congested - Sleep until object wq is congested - * @timoutp: Scheduler sleep timeout - * - * Allow an object handler to sleep until the object workqueue is congested. - * - * The caller must set up a wake up event before calling this and must have set - * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own - * condition before calling this function as no test is made here. - * - * %true is returned if the object wq is congested, %false otherwise. - */ -bool fscache_object_sleep_till_congested(signed long *timeoutp) -{ - wait_queue_head_t *cong_wq = &__get_cpu_var(fscache_object_cong_wait); - DEFINE_WAIT(wait); - - if (fscache_object_congested()) - return true; - - add_wait_queue_exclusive(cong_wq, &wait); - if (!fscache_object_congested()) - *timeoutp = schedule_timeout(*timeoutp); - finish_wait(cong_wq, &wait); - - return fscache_object_congested(); -} -EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested); - -/* - * enqueue the dependents of an object for metadata-type processing - * - the caller must hold the object's lock - * - this may cause an already locked object to wind up being processed again - */ -static void fscache_enqueue_dependents(struct fscache_object *object) -{ - struct fscache_object *dep; - - _enter("{OBJ%x}", object->debug_id); - - if (list_empty(&object->dependents)) - return; - - spin_lock(&object->lock); - - while (!list_empty(&object->dependents)) { - dep = list_entry(object->dependents.next, - struct fscache_object, dep_link); - list_del_init(&dep->dep_link); - - - /* sort onto appropriate lists */ - fscache_enqueue_object(dep); - fscache_put_object(dep); - - if (!list_empty(&object->dependents)) - cond_resched_lock(&object->lock); - } - - spin_unlock(&object->lock); -} - -/* - * remove an object from whatever queue it's waiting on - * - the caller must hold object->lock - */ -void fscache_dequeue_object(struct fscache_object *object) -{ - _enter("{OBJ%x}", object->debug_id); - - if (!list_empty(&object->dep_link)) { - spin_lock(&object->parent->lock); - list_del_init(&object->dep_link); - spin_unlock(&object->parent->lock); - } - - _leave(""); -} - -/** - * fscache_check_aux - Ask the netfs whether an object on disk is still valid - * @object: The object to ask about - * @data: The auxiliary data for the object - * @datalen: The size of the auxiliary data - * - * This function consults the netfs about the coherency state of an object - */ -enum fscache_checkaux fscache_check_aux(struct fscache_object *object, - const void *data, uint16_t datalen) -{ - enum fscache_checkaux result; - - if (!object->cookie->def->check_aux) { - fscache_stat(&fscache_n_checkaux_none); - return FSCACHE_CHECKAUX_OKAY; - } - - result = object->cookie->def->check_aux(object->cookie->netfs_data, - data, datalen); - switch (result) { - /* entry okay as is */ - case FSCACHE_CHECKAUX_OKAY: - fscache_stat(&fscache_n_checkaux_okay); - break; - - /* entry requires update */ - case FSCACHE_CHECKAUX_NEEDS_UPDATE: - fscache_stat(&fscache_n_checkaux_update); - break; - - /* entry requires deletion */ - case FSCACHE_CHECKAUX_OBSOLETE: - fscache_stat(&fscache_n_checkaux_obsolete); - break; - - default: - BUG(); - } - - return result; -} -EXPORT_SYMBOL(fscache_check_aux); |